The clean surface of a Pt(100) single crystal in its stable (5 x 20) and metastable (1 x 1) configurations was investigated by using ultra-violet photo-electron spectroscopy, Auger electron spectroscopy and low-energy electron diffraction. The photo-electron spectrum of the (1 x 1) surface for hν = 11.6 to 40.8eV was characterized by a narrow peak which was 0.25eV below the Fermi level. It was suggested that this peak was due to a maximum in the surface density of states associated with an electronic surface resonance or surface state on the (1 x 1) surface.

Observation of a Change in the Surface Electronic Structure of Pt(100) Induced by Reconstruction. H.P.Bonzel, C.R.Helms, S.Kelemen: Physical Review Letters, 1975, 35, 1237-40